A technique which encourages a driver to improve his/her driving skill and improves fuel efficiency by an improved driving skill has been publicized (for example, see Patent Document 1).
The above technique uses five parameters for judgment: (1) acceleration, (2) deceleration, (3) vehicle velocity, (4) driving in which a driver does not shift up though he/she can do so, and (5) engine idling.
In this technique, if predetermined thresholds for the parameters (1) to (3) are exceeded, the way of driving concerned is decided to have deteriorated fuel efficiency. This means that when such predetermined thresholds are not exceeded, the way of driving is not decided to have deteriorated fuel efficiency. However, the degree of fuel saving in actual situations should be evaluated in connection with each parameter.
Also, in connection with (3) vehicle velocity, this evaluation method has another problem that since an evaluation is made simply on the basis of vehicle velocity without considering the distance traveled from start to stop, the result of evaluation does not always reflect the real cause of fuel efficiency deterioration or improvement.
In order to solve the above problems, the present inventors have provided a fuel consumption evaluation system which obtains quantitative data to determine whether actual driving consumes fuel more efficiently or less efficiently than average driving and gives the driver and/or manager concrete advice for fuel efficient driving based on the obtained data.
This technique correlates the way of driving with fuel consumption per unit distance traveled. However, in actual situations, roads have slopes and the traffic flow varies from time to time, which affects fuel consumption. Therefore, even when the way of driving is constant, fuel consumption per unit distance may easily deviate from the previously estimated level.
Furthermore, although fuel consumption depends on vehicle total mass including freight or passengers, the influence of slopes and vehicle total mass are not reflected in evaluations.
In addition, the primary object of the above techniques is to encourage the driver to do fuel-efficient driving, but they do not define any means to encourage, in real time, the driver to do fuel-efficient driving.
As another approach, a driving information provision system has been proposed in which different analyses of the driver and the manager are made on the basis of travel data obtained from the vehicle and different appropriate suggestions for improvement are given to the driver and the manager (for example, see Patent Document 2).
However, this driving information provision system does not suggest any means for urging fuel-efficient driving in real time.
Patent Document 1: JP-A No. 2002-362185
Patent Document 2: JP-A No. 2003-16572